The specific goal of this Phase II proposal is to develop and clinically test an Untethered Home Sleep Monitor (UHSM). The UHSM will have all the essential capabilities of state-of-the-art clinical systems. The UHSM will not compete with the need for existing sleep laboratories. The UHSM will increase the number of sleep studies those laboratories can complete per night to increase their profits and will give them a tool for studies in nontraditional locations. The ambulatory system will be able to transmit data via an RF link to a nearby computer for real-time monitoring and/or store the data using flash memory for later download. The UHSM will incorporate dry electrodes to reduce setup time and decrease patient discomfort. In addition, software algorithms will detect when electrodes have come loose from a subject and need replacing.The UHSM will be of great utility for clinicians in sleep laboratories. The UHSM will be an economical, convenient, and unobtrusive method for measuring bioelectric and respiratory signals. The UHSM will be clinically tested at a sleep study clinic and compared to standard clinical monitoring equipment. Finally, the UHSM will undergo home sleep studies for analysis of signal quality.